Fixing structure and backlight module using the same

ABSTRACT

A fixing structure and a backlight module using the same are provided. The fixing structure is used for fixing a circuit board. The circuit board with several openings has an upper surface and a lower surface. The fixing structure includes a back plate and several hooks. The back plate has a contact surface. These hooks are disposed on the contact surface. The hooks go through the openings so that the contact surface contacts the lower surface. The hooks move toward the walls of the openings and press against the upper surface so as to fix the circuit board onto the back plate.

This application is a divisional application of co-pending U.S.application Ser. No. 11/802,946, filed May 29, 2007, and claims thebenefit of Taiwan application Serial No. 95137612, filed Oct. 12, 2006,the subject matter of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates in general to a fixing structure, and moreparticularly to a fixing structure applied to a backlight module.

2. Description of the Related Art

In a common backlight module of the liquid crystal display (LCD) device,a cold cathode fluorescent lamp (CCFL) or a light emitting diode (LED)is used as a back light source. In the liquid crystal display devicewith a light emitting diode as the back light source, the light emittingdiode is usually soldered to a printed circuit board (PCB), and theprinted circuit board is fixed onto a back plate of the backlight moduleby screws.

In order to transmit the heat generated by the light emitting diode tothe back plate, the printed circuit board has to be attached to the backplate closely as a smooth flat, so that the light emitting diode couldbe prevented from damaging by the heat. However, the printed circuitboard is usually fixed to the back plate via several screwsconventionally. While inserting the screws into the printed circuitboard, it is very likely to pass over some of the screws accidentally.Even if only a minor number of screws are not inserted into the printedcircuit board, the printed circuit board cannot be fixed to the backplate as a smooth flat. Furthermore, when the screws are all insertedinto the printed circuit board, it is still very difficult to ensurethat every screw applies the same force to the printed circuit board.Therefore, the method of screwing the printed circuit board leads tosome drawbacks, such as increasing the manufacturing cost and theassembling time, and lowering the yield rate and the quality of product.

Therefore, there exists a major issue that needs to be solved to closelyand efficiently fix the printed circuit board onto the back plate in abacklight module.

SUMMARY OF THE INVENTION

The invention is directed to a fixing structure and a backlight moduleusing the same. A circuit board is fixed onto the back plate closely anduniformly through the application of several hooks disposed on a backplate and some openings formed in a circuit board.

According to the present invention, a fixing structure for a circuitboard is provided. The circuit board with several openings has an uppersurface and a lower surface. The fixing structure includes a back plateand several hooks. The back plate has a contact surface. The hooks aredisposed on the contact surface. The hooks go through the openings, sothat the contact surface contacts the lower surface. The hooks movetoward the walls of the openings and press against the upper surface soas to fix the circuit board onto the back plate.

According to the present invention, a backlight module including acircuit board, a light emitting device and a fixing structure isprovided. The circuit board with several openings has an upper surfaceand a lower surface. The light emitting device is disposed on thecircuit board for providing a backlight source. The fixing structureused for fixing the circuit board includes a back plate and severalhooks. The back plate has a contact surface. The hooks are disposed onthe contact surface. The hooks go through the openings, so that thecontact surface contacts the lower surface. The hooks move toward thewalls of the openings and press against the lower surface so as to fixthe circuit board onto the back plate.

According to the present invention, another backlight module including alight source structure and a back plate is provided. The light sourcestructure includes a circuit board and a light emitting device. Thecircuit board with several openings has an upper surface and a lowersurface. The light emitting device is disposed on the circuit board forproviding a backlight module. The back plate includes a fixing structureand a contact surface. The fixing structure used for fixing the circuitboard includes several hooks. The hooks are disposed on the contactsurface. The hooks go through the openings, so that the contact surfacecontacts the lower surface. The hooks move toward the walls of theopenings and press against the upper surface so as to fix the circuitboard onto the back plate.

The invention will become apparent from the following detaileddescription of the preferred but non-limiting embodiments. The followingdescription is made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a backlight module according to a first embodimentof the present invention;

FIG. 1B illustrates a circuit board in FIG. 1A shifted a distance on aback plate;

FIG. 1C is a three dimensional view of the backlight module in FIG.

1B;

FIG. 2 illustrates a backlight module according to a second embodimentof the present invention;

FIG. 3A illustrates a backlight module according to a third embodimentof the present invention; and

FIG. 3B illustrates a circuit board in FIG. 3A shifted a distance on aback plate.

DETAILED DESCRIPTION OF THE INVENTION First Embodiment

Referring to FIG. 1A, a backlight module according to a first embodimentof the present invention is illustrated. The backlight module 20includes a circuit board 21, a light emitting device 22 and a fixingstructure 23. The circuit board 21 with several openings 21 c has anupper surface 21 a and a lower surface 21 b. The light emitting device22 is disposed on the circuit board 21 for providing a backlight source.The fixing structure 23 used for fixing the circuit board 21 includes aback plate 231 and several hooks 232. The back plate 231 has a contactsurface 231 a. The hooks 232 are disposed on the contact surface 231 afor connecting the circuit board 21. The hooks 232 go through theopenings 21 c, so that the contact surface 231 a contacts the lowersurface 21 b. FIG. 1B illustrates the circuit board in FIG. 1A shifted adistance on the back plate. FIG. 1C is a three dimensional view of thebacklight module in FIG. 1B. The circuit board 21 is shifted a distanced1 on the back plate 231, so that the hooks 232 move toward the walls ofthe openings 21 c and press against the upper surface 21 a. Accordingly,the circuit board 21 is fixed onto the back plate 231.

Moreover, each hook 232 has a curve surface 232 b and a connectingsurface 232 a. The curve surface 232 b is disposed at a front edge ofthe connecting surface 232 a. When each hook 232 connects to the circuitboard 21, the circuit board 21 moves to the connecting surface 232 aalong the curve surface 232 b. The height h1 between the connectingsurface 232 a and the back plate 231 is less than the thickness w1 ofthe circuit board 21. Therefore, when each hook 232 connects to thecircuit board 21, the connecting surface 232 a presses against the uppersurface 21 a of the circuit board 21. Each hook 232 applies a force tothe upper surface 21 a, so that the circuit board 21 presses against theback plate 231 closely. Therefore, there is no gap 26 (the gap 26 isshown in FIG. 1A) between the circuit board 21 and the back plate 231.

In the present embodiment, the width of the openings 21 c is at leastequal to the width of the hooks 232 for the hooks 232 going through theopenings 21 c. The back plate 231 is preferably made of metal forproviding sufficient support, so that the backlight module 20 can beprevented from bending, and the circuit board 21 can be maintained in asmooth flat. The hooks 232 and the back plate 231 are preferably formedintegrally to lower the manufacturing cost. The light emitting device 22is a light emitting diode (LED) for example.

In the backlight module 20 of the present embodiment, the hooks 232 gothrough the openings 21 c, and then the circuit board 21 moves adistance d1 on the back plate 231 to fix the circuit board 21. Becauseeach of the hooks 231 matches one opening 21 c, the sideway sliding ofthe circuit board 21 relative to the back plate 231 is confined.Further, the height h1 between the connecting surface 232 a and the backplate 231 is less than the thickness w1 of the circuit board 21, so thecircuit board 21 presses against the back plate 231 closely.Consequently, the circuit board 21 is fixed onto the back plate 231stably and uniformly.

Second Embodiment

Referring to FIG. 2, a backlight module according to a second embodimentof the present invention is illustrated. The backlight module 30includes a circuit board 21, a light emitting device 22 and a fixingstructure 33. The fixing structure 33 for fixing the circuit board 21includes a back plate 231 and several hooks 332. The backlight module 30of the present embodiment and the backlight module 20 of the firstembodiment are different in the design of the hooks 332. The other sameparts are not described repeatedly.

In the present embodiment, each hook 332 has a protruding point 332 a.The height h2 between the protruding point 332 a and the back plate 231is less than the thickness w1 of the circuit board 21. Therefore, wheneach hook 332 is connected to the circuit board 21, the protruding point332 a presses against the upper surface 21 a of the circuit board 21.Each hook 332 applies a force to the upper surface 21 a through theprotruding point 332 a, so that the circuit board 21 presses against theback plate 231 closely.

In the backlight module 30 of the present embodiment, the hooks 332 gothrough the openings 21 c and press against the upper surface 21 a ofthe circuit board 21 through the protruding points 332 a. Therefore, thecircuit board 21 is fixed onto the back plate 231 stably.

Third Embodiment

Referring to FIG. 3A, a backlight module according to a third embodimentof the present invention is illustrated. The backlight module 40includes a light source structure 41 and a back plate 42. The lightsource structure 41 includes a circuit board 411 and a light emittingdevice 412. The circuit board 411 with several openings 411 c has anupper surface 411 a and a lower surface 411 b. The light emitting device412, such as a light emitting diode (LED), is disposed on the circuitboard 411 for providing a backlight source. The back plate 42 includes afixing structure 421 and a contact surface 42 a. The fixing structure421 for fixing the circuit board 411 includes several hooks 422. Thehooks 422 are disposed on the contact surface 42 a for connecting to thecircuit board 411. The hooks 422 go through the openings 411 c, so thatthe contact surface 42 a contacts the lower surface 411 b. Please referto FIG. 3B at the same time. FIG. 3B illustrates the circuit board inFIG. 3A shifted a distance on the back plate. The circuit board 411 isshifted a distance d4 on the back plate 42, so that the hooks 422 movetowards the walls 411 d of the opening 411 c and press against the uppersurface 411 a. As a result, the circuit board 411 is fixed onto the backplate 42.

The wall 411 d of each opening 411 c is a curve surface. The height h4of each hook 422 is less than the thickness w4 of the circuit board 411.When connected to the circuit board 411, each hook 422 moves to theupper surface 411 a along the curve surface. Each hook 422 applies aforce to the upper surface 411 a for pressing the circuit board 411against the back plate 42 closely. As a result, there is no gap 46 (thegap 46 is shown in FIG. 3A) between the circuit board 411 and the backplate 42. The width of the openings 411 c is at least equal to the widthof the hooks 422, so that the hooks 422 are able to go through theopenings 411 c. The back plate 42 is preferably made of metal forproviding enough support, so that the circuit board 411 of the backlightmodule 40 is not warped or even broken due to external force. As aresult, the light source structure 41 provides a uniform back lightsource.

In the backlight module 40 of the present embodiment, the hooks 422 gothrough the openings 411 c and are connected to the circuit board 411.As a result, the light source structure 41 is fixed onto the back plate42 closely, and the circuit board 411 is fixed on the back plate 42.Furthermore, there is no gap 46 between the circuit board 411 and theback plate 42.

In the fixing structure and the backlight module using the sameaccording to the embodiments of the present invention, several hooksdisposed on the back plate are used for matching the openings formed inthe circuit board. As a result, the circuit board is fixed onto the backplate while the hooks are connected to the openings. There is no need toinsert screws, and there would be no miss screwing. As a result, theassembling time is reduced, and the circuit board is disposed flatly dueto the uniform force applied to the circuit board. The fixing structureand the backlight module using the same according to the preferredembodiments described above have at least the following advantages:

1. Only several hooks are needed to be disposed on the back plate, andseveral corresponding openings are formed on the circuit board to fixthe circuit board onto the back plate stably and closely. The structureis simple, so the cost for developing complex mold is saved.

2. While fixing the circuit board onto the back plate, the hooks gothrough the openings, and the circuit board moves a distance on the backplate. The steps of fixing the circuit board are quick and easy.

3. Each hook goes through one opening correspondingly. As a result, thesideway sliding of the circuit board relative to the back plate isprevented after being fixed.

4. Several hooks are connected to the circuit board to fix the circuitboard to the back plate closely. The flatness of the circuit board ismaintained, and the product quality and yield rate are improvedaccordingly.

While the invention has been described by way of example and in terms ofseveral preferred embodiments, it is to be understood that the inventionis not limited thereto. On the contrary, it is intended to cover variousmodifications and similar arrangements and procedures, and the scope ofthe appended claims therefore should be accorded the broadestinterpretation so as to encompass all such modifications and similararrangements and procedures.

1. A fixing structure for fixing a circuit board with a plurality ofopenings, the circuit board having an upper surface and a lower surface,the fixing structure comprising: a back plate having a contact surface;and a plurality of hooks disposed on the contact surface; wherein thehooks go through the openings, and the hooks move toward the walls ofthe openings and press against the upper surface so as to fix thecircuit board onto the back plate; wherein when the circuit board isfixed onto the back plate, the contact surface contacts the lowersurface.
 2. The fixing structure according to claim 1, wherein each hookhas a connecting surface, and when the hook is connected to the circuitboard, the connecting surface presses against the upper surface of thecircuit board.
 3. The fixing structure according to claim 2, wherein theheight between the connecting surface and the back plate is less thanthe thickness of the circuit board.
 4. The fixing structure according toclaim 2, wherein each hook has a curve surface formed at a front edge ofthe connecting surface.
 5. The fixing structure according to claim 2,wherein each hook comprises a protruding point formed on the connectingsurface.
 6. The fixing structure according to claim 5, wherein theheight between the protruding point and the back plate is less than thethickness of the circuit board.
 7. The fixing structure according toclaim 1, wherein the wall of each opening is a curve surface.
 8. Thefixing structure according to claim 1, wherein the width of the openingsis at least equal to the width of the hooks.